Specifications
2.3 TRANSCEIVER ADJUSTMENTS
The SW-1000-SC provides adjustment controls for squelch (SQ), voice-operated transmitter
(VOX) sensitivity, receive volume (RV), side audio (ST), intercom volume (IV), and channel
selection. Most adjustments are made on the surface, not while diving. There are two options
for transmission: VOX (voice activation) and push-to-talk (PTT). The sensitivity control
for the VOX is a two-turn level control located on the lower half of the upper electronics
housing (Fig. 6 in Section 6). This adjustment must be made in a dry environment. To switch
from VOX to PTT or vice versa, you simply depress the PTT button three times within 2
seconds. You will hear a long tone indicating VOX and a short tone indicating the PTT mode.
The switch for channel selection and all two-turn adjustments for squelch sensitivity, side
audio, intercom, and VOX are located on the lower side of the upper electronics module.
To access these adjustments, remove and set aside the lower battery housing and locate
the controls on the electronics module’s lower side. Adjustments will be discussed fully in
Section 6, Advanced User Information.
2.4 VOICE-OPERATED TRANSMITTER (VOX)
VOX operation provides hands-free communications. The user simply talks for the unit
to transmit automatically. The VOX sensitivity needs to be set according to the diver’s
voice. Improper VOX adjustment may result in false transmission or inability to transmit.
VOX mode can be overridden with the PTT control. Overriding the VOX mode via the
PTT switch automatically switches the transceiver to the PTT mode. Tests have shown
most divers favor the PTT mode over the VOX mode.
2.5 PUSH-TO-TALK SWITCH (PTT)
A unique feature of the SW-1000-SC is electronic switching between the VOX and PTT
modes while underwater, not only on the surface. The location of the PTT button varies
among earphone-microphone assemblies, because of the many congurations of full-face
masks and rebreather mouthpieces. In the PTT mode the button is simply pressed to
transmit. Upon release of the PTT button, the system automatically returns to the receive
mode. The PTT function overrides the VOX function. The PTT button is used also to
switch the transceiver from VOX to PTT or vice versa. See Section 3.4.1, Push-to-Talk
(PTT) Button, for further instructions.
2.6 SQUELCH (SQ)
The squelch provides a means to limit the background noise heard by the diver. The
setting will depend on the specic requirements of the dive. If long range is desired,
minimal or no squelch should be used. If working close-range to other divers and/
or the surface station, an increased setting can be used. (Note: An increased setting is
appropriate for most SDV training operations.) For most operations a setting of one-half
turn counterclockwise from fully clockwise is optimum.
2.7 SIDE AUDIO VOLUME (ST)
When you transmit, you will hear yourself via your earphone. This is called “Side Audio”
(“Sidetone,” ST). It is useful for verifying that you are transmitting. Some full-face masks
or helmets may have a conguration that causes feedback between the microphone and
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